Brake rigging



Ndv. 12, 1940. 'r. R. MCGOWAN BRAKE RIGGI'NG Filed Sept. 16, 1938INVEN'VIOR Thom M Gowan,

BY I

' HIS ATTORNEY Patented Nov. 12, 1940 UNITED STATES 2,221,114 BRAKERIGGING Thomas McGowan, Pittsburgh, Pa. assignor to The American BrakeCompany, Swissvale, Pa.,

a corporation of Missouri Application September 16, 1938, Serial No.230,295

' vol-aim (01. 18858) My invention relates to brake rigging, :andparticularly to brake rigging of the clasp type for railway vehicletrucks which are intended to be used on, modern high speed trains. Withclasp. brakes as they are now generally constructed, when a. brakeapplication takes place, the. frictional forces. which. are set. up bythe rotation of the wheels tendto move one shoe oneach wheel downwardlyand the other shoe upwardly. Furthermore, if the shoes, are hung belowthe horizontal center lines of the wheels as frequently happens forclearance. or other practical reasons, the forces which. are exerted onthe shoes to move theminto frictional engagement with the wheels cause adownward component to be exerted onthe shoes which tends to move themdownwardly along. the treads of the wheels. These two forces will ofcourse tend to ofiset each otherin the. case of the. shoe. which isurged upwardly by the frictional force, but it has been ascertained thatthe downward force will always exceed the upward force, so that the nettendency of the forces exerted on both shoes is to move the shoesdownwardly relative to the wheels. ,The downward forces which areexerted on the shoes. are of course transmitted to the portion of thetruck which supports the brake rigging, and when this portion of thetruck. is, the. frame as has heretofor generally been the. case, thesereaction forces. must be. resisted by the truckv springs. As long as thecar speeds, are. relatively low, the brake shoe pressures required are.relatively low, and under these conditions the reaction forces which aretransmitted to the frame are insufficient to b objectionable. However,as the car speed increases, the brake shoe pressures re-. quiredincrease with the result that. at. the higher car speeds the. reactionforces become sufiicient ly great to pull the truck frame downwardlyuntil it meets a solid stop, or at least until the truck. springs becomesubstantially fully compressed, it being noted that as the springsbecome compressed, the. distance between the brake shoes and thehorizontal center line. of the wheels increases which acts tofurtherincrease the downward force component acting on the truck frame.When the truck springs become compressed, the wheels cannot fully adjust50 themselves to vertical inequalities inthe track rails, and, as one ormore of the wheels pass over the uneven sections of the rails, they mayforan instant have atendency to leave the rails, or to at least have agreatly reduced frictional contact, therewith. The tendency of thewheels to means for preventing its occurrence.

slide is thereby greatly increased, and since wheel sliding is, ;forwell-known reasons, very objectionable, it is extremely desirabletoprovide Moreover, .when the brake rigging is of the usualtype in whichthe brake shoes are located below the. horizontal. center line of thewheels, and the brake rigging ismounted on the truck in such manner,that the reaction forces which are. set up when a brakeapplication,occurs cause the truck springs to become compressed, and the brakecylinderpressure is reduced following a heavy brake application toefifecta .partial release of the brakes, the compressed springs actthrough the medium of the truck frame and brake riggingwto cause theshoes to move upwardly-toward the horizontalcenter line of the wheels.This upward movement of the brake shoes tends-to maintain them inbraking engagement with the wheels, and thereby offsets to a large.extent the reduction in brake cylinder pressure which caused theirupward movement until the. shoes have. been. moved to their normalpositions, at which-time the action of the springs ceases and. the.partial release of the brakes is finally effected through a furtherreduction in brake cylinder pressure. In braking high speed trains ,itis desirable to be able to effect a quick partial release of the, brakeswith a minimum reductionin brake cylinder pressure to maintain thevmaximum braking effect and still prevent wheel slippage, and. thisupward movement of the. brake shoes, by the truck springs greatlyincreases the reduction in brake-cylinder pressure which. must be madebefore the properpartial' release (can be effected, and hencedelays therelease. of the. brakes. It follows, therefore, that it. is also.desirable to provide means for avoiding thisundesirable"condition.

With theabove and other considerations in view, one objectl of vmyinvention 'is to provide means 'for mounting brake rigging on a cartruck in such manner that the, forces which are set up in the brakerigging when a brake application takes place. will not be transmitted tothe truck frame,

Another objectof my invention is toprovide brakerigging'for vehicletrucks which will permit a relative'lyhigh braking power of the order of250 per cent" of the weight on the truck to be applied'to the truckwheels without causing the truck frame to tip or move downwardly due tothe forces which are set up in the brake rigging when the brakes areapplied.

A further object of'my invention is to provide means for supporting thebrake rigging on a car truck in such manner that the supportings meansand brake rigging can readily be re moved from the truck as a unit.

A further object of my invention is the provision of brake rigging inwhich the rotation of the wheels may be retarded without applyingfriction to that portion of the wheels which runs on the rails andcarries the weight.

A still further object of my invention is to mount brake drums inboardof the wheels where there is adequate clearance, and to support brakerigging of the clasp type for cooperation with these brake drums bymeans of a brake carrier which is journaled on the axles between thedrums and which is wholly independent of the truck frame.

Other objects and characteristic features of my invention will appear asthe description proceeds.

I shall describe one form of brake rigging 'embodying my invention, andshall then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a side elevational view of arailway car truck provided with brake rigging embodying my invention,only a portion of the truck frame being shown to improve the showing ofthe brake rigging. Fig. 2 is a top plan View of the truck and brakerigging shown in Fig. 1. Fig. 3 is a right-hand end view of that portionof the brake rigging which is associated with the right-hand wheel andaxle assembly in Figs. 1 and 2.

Similar reference characters refer to similar parts in each of theseveral views.

Referring to the drawing, I have here shown my invention applied to afour-wheel car truck comprising a truck frame I supported at one end bya wheel and axle assembly consisting of a pair of wheels 2 mounted on anaxle 3, and at the other end by a wheel and axle assembly consisting ofa pair of wheels 4 mounted on an' axle 5. The truck frame I may have anypreferredconstruction, and as here illustrated includes spaced sidemembers Ia connectedtogether by transversely extending end members lb,and spaced center members or transoms lo and Id between which aconventional spring plank B is located. The means for supporting thetruck frame by the wheel and axle assemblies, as well as the means forsupporting the spring plank by the transoms are not shown because these.means are well-known and comprise no part of my present invention.

The axles 3 and 5 are provided with centrally located bearingportions 1. and 8 defined at their ends by annular shoulders 1a and 8a,respectively, and disposed ,on each of these bearing portions are twopairs of bearing blocks [0. The bearing blocks l0 support alongitudinally extendin brake carrier ll through the medium of pedestajaws I2 which are formed on the carrier, and which receive the blocks ina manner to permit vertical sliding movementof the carrier relative tothe upper block; and interposed between the upper block of eachpair' andthe top of the jaw is a coil spring I3, the, function of wh ch is tocushion the carrier and parts mounted thereon against excessive shockdue to the hammering which takes place between the wheels and the rails.A bolt l4 .extends through the lower block of eachpair and through thelower ends of the pedestal legs l5 of the associated pedestal jaw, andserves with thelower block as a means to limit the vertical movement ofthe carrier relative to the axles. It will be noted that the centralportion of the carrier extends below the spring plank, and it should bepointed out that all parts of the carrier are so located as not tointerfere in any way with the truck frame or any other part or parts ofthe truck. It should also be pointed out that by dropping the wheel andaxle assemblies and then removing the bolts Hi, the carrier and partsattached thereto can be removed as a unit from the axles to permit thebearing blocks to be replaced when they become worn, or for any otherreason which may make it necessary or desirable to remove the brakecarrier from the truck.

The brake carrier supports the brake rigging which, in'the form hereillustrated, comprises two separate and independent brake mechanisms oneof which is associated with each wheel and axle assembly. These twomechanisms are similar, and a description of one will therefore sufficefor both. I

Referring particularly to the brake mechanism associated with the wheels2 and axle 3, this mechanism is actuated by a brake cylinder 20 which ashere shown is mounted on a platform 2| formed on the brake carrier ldirectly in rear of the axle 2 in line with the center line of thetruck. The brake cylinder 28 is of the usual and well-knownconstruction, and includes the usual cylinder body, reciprocable piston(not shown) biased to the inner end of its stroke by the usual releasespring (not shown), and a push rod 22 which is operatively connected atits inner end withv the piston.

The outer end of push rod 22 is operatively connected by means of a pin23 with an equalizing lever 24 intermediate its ends, and the equalizinglever24, in turn, is operatively connected at its ends through themedium of pull rods 25 and 26 with the upperends of a pair of floatinglive levers 21 and 28, respectively. The live levers 21 and 28 extenddownwardly through lever slots 29 and 38 formed on the brake carrier andare movably supported from the brake carrier by means of pin and rollerassemblies 32.

The pin and roller assemblies are secured to the levers adjacenttheirupper ends, and the rollers of these assemblies rideon. the brakecarrier on opposite sides of the lever slots.

Intermediate their ends, the live levers 21 and 23 are connected throughthe medium of double jaws 34 and 35, respectively, with a brake beam 36.The brake beam 36 is suspended from the brake carrier by means of hangerlinks 31, the lower ends of which receive trunnions formed on the endsof the beam, and the upper ends of which are pivoted on pins 38 mountedin bifurcations 39 formed on laterally projecting arms. 40 provided onthe brake carrier. The trunnions formed on the end of the brake beam 36also pivotally support brake heads 4| which carry brake shoes 42. forcooperation with brakedrums 43 and 44 mounted .on the axle 2 inboard ofthe wheels 3 on opposite sides of the bearing portion 8.

The lower ends of the live levers 21 and 28 are connected with a brakebeam 41 at points equally spaced from its ends by means of pull rods 48and 49. The pull rods 48 and 49 are each provided at the end which isconnected to the associated live lever with aslack adjuster 50 ofwellknown construction, and at the .opposite end with a jaw 5| whichreceives the brakelbeam.

brake carrier by means of dead levers 52 and 53,

- in the cylinders.

the lower ends of which receive trunnions formed on the opposite ends ofthebrake. beam,.and the upper ends of which are pivoted on: pins154mounted in bifurcations: 55 provided ontdiverging arms 56 formed on theforward end of the brake carrier. Each of the dead levers 52' and 53 isprovided intermediate its ends with a brake head 5'! carrying a brakeshoe 58 for cooperation with the associated brake drum 43 or 44.

When it is desired to effect an application of the brakes, fluidpressure is simultaneously supplied to both brake cylinders in the usualmanner, thereby forcing the push rods 22 outwardly This outward movementof the push rods acts through the associated equalizing lever 24 andassociated'pull'rods 25 and 25 to move the upper ends of the live levers21 and 28 in the same direction as the push' rods are moved and withequal'forces. This movement of the live levers, in turn,'acts throughthe double jaws 34 and 35 and brake beam 36 to move the brake shoes 42into frictional engagement with the associated drums 43 and 44, andthrough the pull rods 48 and 49, brake beam 41 and 'dead levers 52 and53 to move the brake shoes 58 into frictional engagement with theforward sides of the brake drums, thereby applying clasp brakes to thebrake drums, and hence applying braking power to the. wheels. When thebrake shoes move into frictional engagement with the'brake drums, thereaction forces set up cause the cushioning springs l3 to becomecompressed and allow the brake carrier to'move downwardly to the pointin which the upper bearing blocks l0 engage the topsof the pedestaljaws, but the amount of movement of the carrier which can take placeunder these conditions is not suflicient to materially affect theoperation of the brake mechanism or the forces developed.

When it is desired to release the brakes, the fluid pressure which wassupplied to the brake cylinders is vented to atmosphere, and the releasesprings in the brake cylinders then function to restore the push rods totheir retracted positions and thereby effect the release of the brakes.

One advantage of brake rigging constructed in the manner described isthat inasmuch as the brake rigging is suspended from a brake carrierwhich is journaled directly on the axles and which is wholly independentof the truck frame, none of the reaction forces which are set up duringa brake application are transmitted to the truck frame, and as a resultany downward movement of the frame or any tipping due to the forceswhich are set up in the brake rigging has been eliminated. The ridingqualities of the car are therefore improved as well as the life of thetruck.

Another advantage of brake rigging constructed in the manner describedis that since the brake rigging is suspended from the truck by means ofa separate brake carrier in the manner described, the brake shoes arealways maintained in proper operative relation to the braking surfaces,which increases the efiiciency of the brake rigging and permits heavybraking powers of the order of 250 per cent of the weight on the truckto be applied to the wheels to effect rapid deceleration of high speedtrains. The fact that the shoes are always maintained in properoperative relation with the wheels also greatly facilitates a quickpartial release of the brakes at all times following a brakeapplication.

A further advantage of brake rigging constructed in the manner describedis that since the brake shoes are applied to brake drums rather than tothe wheels, the braking surfaces can be made largerthan'woiuld'otherwise be possible,.thereby permitting a reduction. inthe unit shoefipressure. Moreover, wear on the wheels due to the brakeshoes is eliminated and damage to the wheel tread due to the heat ofbrake. shoe friction is prevented.-

lilthough I have herein shown and described only one form of brakerigging embodying my invention, it is understood that various changesand modifications may be made therein within the scope of the appendedclaims without departingv from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a railway vehicle truck comprising. a truck frame mounted onspaced wheel and axle assemblies, a brake carrier independent of thetruck frame journaled on said wheel and axle assemblies and held in asubstantially fixed position relative to the axes of said wheel and axleassemblies, brake riggingmounted solely on said carrier capable ofmaking heavy brake applications. to said truck, and means for cushioningsaid carrier against shocks in such manner that said brake rigging willbe retained in proper operative relation with said wheel and axleassemblies during heavy applications of the brakes irrespective of saidcushioning means.

2. In a railway vehicletruck i comprising a truck frame mounted .onspaced wheel and axle assemblies, av pair of brake drums mounted on eachaxle inboard of the wheels, a brake carrier independent of thetruckframe'journaled on said axles between said brake drums and held ina substantially fixed position relative to the axes of said axles, abrake cylinder mounted on said carrier between the drums of each pair,and

means supported from said carrier and actuated by said cylinder forapplying clasp brakes to each brake drum.

3. In a railway vehicle truck comprising a truck frame mounted on spacedwheel and axle assemblies, a brake carrier independent of the truckframe journaled on said axles by means which holds said carrier in asubstantially fixed position relative to the axes of said axles, a pairof brake drums mounted on each axle on opposite sides of said carrier, apair of dead levers associated with each wheel and axle assembly, eachsaid dead lever being suspended from the brake carrier adjacent one sideof an associated brake drum and being provided intermediate its endswith a brake element for cooperation with the associated drum, a firstbrake beam supported by each pair of dead levers at one side of theassociated drums, a pair of live levers associated with each wheel andaxle assembly, each said live lever being suspended from the brakecarrier adjacent a different brake drum at the side opposite to theassociated dead lever, pull rods connecting the lower ends of said livelevers with said first brake beam, a second brake beam suspended fromsaid carrier by means of hangers adjacent each pair of live levers andconnected with said live levers intermediate their ends, brake elementsmounted on each end of said second brake beams for cooperation with theassociated drums, and means connected with the upper ends of said livelevers for actuating them.

4. In a railway vehicle truck, the combination with a truck framemounted on spaced wheel and axle assemblies, of pairs of live and deadtruck levers movably supported from a brake carrier journaled on theaxles, said brake carrier being independent of the truck frame and beingheld in a substantially fixed position relative to the axes of saidaxles, brake elements secured to said dead truck levers intermediatetheir ends for cooperation with braking surfaces rotatable with thewheels, a brake beam supported by each pair of dead levers and connectedby means of pull rods with the lower ends of the associated pair of livelevers, other brake beams supported from said'carrier adjacent eachwheel and axle assembly by means of hangers suspended from said carrierand each connected with the associated pair of live levers intermediatetheir ends and each provided at each end with brake elements forcooperation with said braking surfaces, and means connected with theupper ends of said live levers for actuating them.

5. In a railway vehicle truck, the combination with a truck framemounted on spaced wheel and axle assemblies, of pairs of live and deadtruck levers movably supported from a brake carrier journaled on theaxles, said brake carrier being independent of the truck frame and beingheld in a substantially fixed position relative to the axes of saidaxles, brake elements secured to said dead truck levers intermediatetheir ends for cooperation with braking surfaces rotatable with thewheels, a brake beam supported by each pair of dead levers and connectedby means of pull rods with the lower ends of the associated pair of livelevers, other brake beams supported from said carrier by means ofhangers suspended from said carrier and each connected with theassociated pair of live levers intermediate their ends and each providedat its ends with brake elements for cooperation with said brakingsurfaces, a brake cylinder secured to said brake carrier'at each end ofthe truck and provided with a push rod, and an equalizer associated witheach brake cylinder and pivotally connected intermediate its ends to theassociated push rod and connected at its ends by means of pull rods tothe upper ends of the associated pair of live levers for actuating them.

6. In a railway vehicle truck, the combination with spaced wheel andaxle assemblies, of a brake carrier journaled on said axles, a pair ofbrake drums mounted on one axle on opposite sides of said carrier, apair of live levers extending downwardly through lever slots provided insaid carrier and supported from the carrier by means of pinand rollerassemblies the rollers of which ride on the carrier on opposite sides ofsaid slots, and means connected with said live levers intermediate theirends and at their lower ends respectively and responsive to a forceapplied to the upper ends of said live levers for applying clasp brakesto said brake drums.

7. In a railway vehicle truck, the combination with spaced wheel andaxle assemblies, of a brake carrier journaled on said axles, a pair ofbrake drums mounted on one axle on opposite sides of said carrier, andmeans for applying clasp brakes to said brake drums including a pair oflive levers extending downwardly through lever slots provided in saidcarrier and supported from the carrier by means of pin and rollerassemblies.

' THOMAS R. MCGOWAN.

